1. Field of the Invention
This invention pertains generally to compact antennas, and more particularly to electrically small, split-ring antennas.
2. Description of Related Art
The general purpose of an electromagnetic antenna is to launch energy into free space. It is well known that small physical size, low cost, broad bandwidth, and good radiation efficiency are desirable features for an integrated antenna in the system. It is also well known that generally the quality factor (Q) and the radiation loss of the antenna are inversely related to the antenna size. Therefore those requirements are usually contradictory and traditional electrically small antennas (ESAs) are considered to exhibit poor radiation performance. Existing small antenna designs cannot provide good performance for practical applications.
Some of the antenna designs improve their performance by loading with the metamaterials, which is difficult to realize. For example, a PIFA type or quarter-wavelength microstrip patch antenna has been proposed for size reduction.
Accordingly, an object of the present invention is the use of a vertical split-ring resonator as a metamaterial particle to reduce the antenna size.